How does this medication work? What will it do for me?

Hydroxyurea belongs to the group of cancer-fighting medications known as antineoplastics, and specifically to the group of antineoplastics known as antimetabolites. Hydroxyurea fights cancer by preventing the growth of cancer cells, which eventually results in their destruction. It is usually used to treat certain types of cancers of the skin on the head and neck (excluding the lip) known as squamous cell carcinomas. When treating these types of cancers, hydroxyurea is usually used at the same time as radiation therapy, as these two methods work together to kill cancer cells more effectively.

It can also be used to treat skin cancers known as melanomas, and a certain type of cancer of the blood known as chronic myelocyticleukemia.

It generally takes at least 6 weeks to determine whether treatment with hydroxyurea is effective.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

How should I use this medication?

The recommended dose of hydroxyurea varies according to the specific condition being treated, the response to therapy, the other medications used, whether radiation is being used at the same time, the stage of condition, and the body weight of the recipient.

For the treatment of tumours, of the head and neck, the usual adult dose is 80 mg per kilogram of body weight taken in one dose every third day. If radiation is also being used, hydoxyurea dosing should start at least 7 days before the start of radiation and continue throughout and after treatment, unless there are extreme side effects.

For the treatment of resistant chronic myelocytic leukemia, the recommended adult dose is 20 to 30 mg per kilogram of body weight taken daily.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor. If you cannot swallow capsules, you may empty the contents of the capsule into a glass of water and drink it immediately. Be very careful not to inhale the powder or let it come in contact with your skin or mucous membranes. If you spill the powder, wipe it up immediately with a damp towel and dispose of it along with the empty capsules. Empty capsules should be disposed of in a closed container, such as a plastic bag.

If you vomit shortly after taking the medication, contact your doctor for instruction on whether to take more medication or not. If you miss a dose of this medication, call your doctor for instructions on how to proceed. Do not take a double dose to make up for a missed dose.

Your doctor may want you to drink extra fluids while taking this medication in order to help you pass more fluid and protect your kidneys.

As well as interfering with the genetic material DNA of cancer cells, hydroxyurea can interfere with some of your normal cells. This can cause a number of side effects such as mouth sores. Keep track of any side effects and report them to your doctor as suggested in the section "What side effects are possible with this medication?"

Store this medication at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Do not take this medication if you:

are allergic to hydroxyurea or any ingredients of the medication

have a very low platelet count

have a very low white blood cell count

have severe anemia

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

constipation

diarrhea

dizziness

drowsiness

headache

loss of appetite

nausea

redness of skin where radiation took place

temporary hair loss

vomiting

Although most of these side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Your doctor will do blood tests regularly to monitor the number of specific types of blood cells, including red blood cells, in your blood.

Birth Control: There is the possibility of birth defects if either the father or mother is using hydroxyurea at the time of conception. Men should use effective birth control while taking hydroxyurea and for at least 1 year after completing treatment.

Blood clotting: This medication can reduce the number of platelet cells in the blood. Platelets help the blood to clot, and a shortage could make you bleed more easily. If you notice any signs of bleeding, such as frequent nosebleeds, unexplained bruising, cuts that won't stop bleeding, or black and tarry stools, notify your doctor as soon as possible. Your doctor will order routine blood tests to make sure potential problems are caught early.

Fertility: Men who take hydroxyurea may experience a decrease in the number of healthy sperm produced. Sometimes this is reversible when the medication is stopped. If you are considering starting a family after treatment with hydroxyurea, talk to your doctor.

Gout: Hydroxyurea may increase the level of uric acid in the body. If you develop painful, warm and swollen joints or difficulty with urination, contact your doctor as soon as possible.

If you have a history of gout, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Infection: As well as killing cancer cells, hydroxyurea can reduce the number of cells that fight infection in the body (white blood cells). If possible, avoid contact with people with contagious infections. Tell your doctor immediately if you begin to notice signs of an infection, such as fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness. Your doctor will do blood tests regularly to monitor the number of specific types of blood cells in your blood.

Kidney function: Kidney disease or reduced kidney function may cause this medication to build up in the body, causing side effects. If you have reduced kidney function or kidney disease, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Liver function: Hydroxyurea may reduce liver function and can cause liver failure. If you have liver problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking this medication.

Tumour Lysis Syndrome: Hydroxyurea, like many other cancer medications, causes many cancer cells to be suddenly killed when treatment is first started. This can overwhelm the body with waste products from the cells. As a result, the body may not be able to keep up with getting rid of all the waste. When this happens, you may experience nausea, shortness of breath, notice cloudy urine, or joint pain. This is called tumour lysis syndrome. Your doctor may prescribe some medications to help your body get rid of the waste products. Make sure you understand how to use these medications and report any of these signs or symptoms to your doctor immediately.

Vaccinations: The effect of vaccines given to people with reduced immune system activity is unpredictable. Hydroxyurea may cause vaccines to be less effective than expected. Talk to your doctor if you need any vaccinations while taking this medication.

Pregnancy: This medication may harm the baby if taken during pregnancy and should not be used during pregnancy. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are a breast-feeding mother and are taking hydroxyurea, it may affect your baby. Because of the risks associated with this medication, women taking this medication should not breast-feed.

Children: The safety and effectiveness of using this medication have not been established for children.

Seniors: Seniors may be more at risk of developing side effects from this medication.

What other drugs could interact with this medication?

There may be an interaction between hydroxyurea and any of the following:

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

stop taking one of the medications,

change one of the medications to another,

change how you are taking one or both of the medications, or

leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. In many cases, interactions are intended or are managed by close monitoring. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, decongestants, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.